Impact of CArdiopulmonary Bypass Flow on Renal Blood Flow, Function and OXygenation

Cardiac surgery with cardiopulmonary bypass (CPB), especially when oxygen delivery is low, is associated with acute kidney injury. Unpublished data shows that renal oxygen delivery is compromised during CPB due to low hematocrit and redistribution of blood flow away from the kidneys. We wish to study if increased CPB flow can improve renal oxygenation. Patients who develop cardiac failure after weaning from CPB will be treated as per our departments routine with the inotropic agent milrinone, and measurements will be made before and after treatment.